Recommended settings for DB CFG parameters
For optimal performance, follow the recommended settings for DB2®.
The parameters and values described in the following table are recommended:
| Parameter | Recommended value |
|---|---|
| SELF_TUNING_MEM |
Enables the DB2 self-tuning memory manager (STMM) to automatically and dynamically set memory allocations to memory consumers such as buffer pools, lock lists, package cache, and sort heap. Recommended value: ON |
| DATABASE_MEMORY |
Allows DB2 to adjust the amount of database memory depending on load, memory pressures, and other factors. Recommended values: AUTOMATIC |
| LOCKLIST |
Allows STMM to dynamically manage memory allocations. Recommended value: AUTOMATIC |
| MAXLOCKS |
Allows STMM to dynamically manage memory allocations. Recommended values: AUTOMATIC If AUTOMATIC is not supported: 100 |
| PCKCACHESZ |
Allows STMM to dynamically manage memory allocations. Recommended value: AUTOMATIC |
| SHEAPTHRES_SHR | |
| SORTHEAP | |
| NUM_IOCLEANERS | Recommended value: AUTOMATIC |
| NUM_IOSERVERS | Recommended value: AUTOMATIC |
| DFT_PREFETCH_SZ | Recommended value: AUTOMATIC |
| MAXAPPLS | Recommended value: AUTOMATIC |
| APPLHEAPSZ |
Recommended value: AUTOMATIC |
| APPL_MEMORY | Recommended value: AUTOMATIC |
| DBHEAP |
Amount required depends on the amount of memory available and the traffic volume. Recommended value: AUTOMATIC Note: The default DBHEAP value is inadequate.
|
| LOGFILSIZ |
Refer to the topic Log Configuration. Recommended value: 65536 if configuring 20 transaction logs of 256 MB (65536 4 K pages) |
| LOGPRIMARY |
Number of primary transaction logs. Refer to the topic Log Configuration. Recommended value: 40 or more |
| LOGSECOND |
Number of secondary transaction logs. These are allocated by DB2 when it cannot reuse any of the primary logs due to active transactions. Refer to the topic Log Configuration. Recommended value: 12 |
| NUM_LOG_SPAN |
Refer to the topic Log Configuration. Recommended value: LOGPRIMARY - Safety buffer |
| DFT_DEGREE |
Sets the default degree of parallelism for intrapartition parallelism. In general, online transactional applications such as Sterling B2B Integrator typically experience a high volume of short queries that do not benefit from parallel queries. Recommended value: 1 – Disable intrapartition parallelism |
| DB2LOCK_TO_RB | Recommended value: STATEMENT |